Monday, March 7, 2011

Compressed Natural Gas (CNG) is truly a renewable resource

Compressed Natural Gas (CNG) is truly a renewable resource because it is a resource that can be created in a relatively short amount of time in contrast to Petroleum or Coal. Today there are towns in the United States that are built on top of landfills and are powered totally but the synthetic fuel that is created by the landfill. Synthetic fuels include Methane which is also called Natural Gas. Natural Landfill Gas is formed in four phases as depicted in the following graph.
Phase 1: In phase of decomposition, aerobic bacteria consume oxygen while breaking down carbs, proteins, and fats that compose organic waste. This process creates carbon dioxide. Phase 1 can last from weeks to months.
Phase 2: After the oxygen has been consumed the bacteria uses an anaerobic process to convert compounds in to acetic, lactic, and formic acids and alcohols such as methanol and ethanol. The landfill becomes highly acidic and as the acids mix with the moisture in the landfill, nutrients dissolve making nitrogen and phosphorus available to the increasingly diverse species of bacteria in the landfill. These diverse bacteria create gaseous by-products.
Phase 3: Once the anaerobic bacteria consume the organic acids produced in phase 2 the landfill becomes a more neutral environment in which methane-producing bacteria begin to establish themselves. Methanogenic bacteria consume carbon dioxide and acetate.
Phase 4: The gas produced in this phase contains methane, carbon dioxide and other gases such as sulfides. The gas takes as about 20 years to develop but the gas will continue to be emitted for 50 years after the waste is placed in the landfill.

Speight Ph.D., D. Sc., J. G. (2008). Synthetic fuels handbook: properties, process, and performance. : The McGraw-Hill Companies, Inc.

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